You have to watch some of those resins. They aren't made for thick casts. I don't think any are cheap, just some a little less than others. I have found over the years of experimenting that you can't always put a price on success. I've wasted lots of time, money, and material trying to get something to work because I didn't want to use what I know would work because of the price. I ended up paying more for it in the long run and ruined some very nice material in the process. Like said above, I think Alumilite is your best chance for a successful cast and finished product. You can conserve resin by finding something to cast your wood in that's close to the size of your finished product, or start with some small products to sell and build up the funds for the larger one. I hope you find what works for you.